Oxidation of NH 3 on V/Ti oxide based catalysts prepared by precipitation

• Published in: Catalysis today Vol. 4; no. 2; pp. 253 - 265
• Main Authors: Cavani, F., Trifiro, F.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 1989
• ISSN: 0920-5861; 1873-4308
• DOI: 10.1016/0920-5861(89)85054-0

V/Ti/O catalysts were prepared by precipitation from mixed solutions of V(IV) and Ti(IV) ions, and tested in the reaction of ammonia combustion to N 2. At low temperature of hydrolysis (lower than 100°C) or low pH of hydrolysis (less than 1.2) the rutile structure for TiO 2 was finally obtained; otherwise TiO 2 was obtained in the anatase form. The samples were characterized with various techniques; different vanadia species identified : i) crystalline or amorphous V 2O 5, weakly interacting with the TiO 2; ii) a species constituting a monolayer spread over the TiO 2 surface, and strongly interacting with it; it is present in either the reduced (V(IV)) or oxidized (V(V)) state, depending upon the crystalline structure of TiO 2; iii) an oxidized V(V) species, probably spread over the monolayer. The latter species, prevalent at high V 2O 5 total charge, is the one responsible for NH 3 overoxidation to N 2.